Determination of object-specific effective errors in the Lyα radial profile. Top panel: the black lines show the extracted profiles from 100 empty locations for the same wavelength bands as the Lyα NB image of the indicated object. The overplotted green line delineates the median at each radius, and the green error bars show the estimated effective noise σ_eff (see text). This procedure was repeated for each object. Bottom panel: 1σ surface brightness sensitivities for the Lyα NB profiles of all objects in our sample, within circular concentric annuli of width 0.̋2 (= size of 1 MUSE spaxel) as a function of radius.